Cell Cycle & Cell Division part 1

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  1. Multicellular organisms use cell division for
    • reproduction
    • growth
    • regeneration (repair of tissues)

    Unicellular organisms use cell division primarily for reproduction.
  2. 4 events must occur for cell division:
    • reproductive signal: initiates cell division
    • replication: of DNA
    • segregation: distribution of the DNA into 2 new cells
    • cytokinesis: separation of the 2 new cells
  3. During __, the cell nucleus is visible and cell functions including replication occur.
  4. Interphase begins after __ & ends when __ starts.
    cytokinesis; mitosis
  5. 3 subphases of interphase
    • G1
    • S
    • G2
  6. In __, chromosomes are single, unreplicated structures. There are __ chromosomes.
    G1; 46

    Neurons will stay in G1 and not divide.
  7. During __, the DNA replicates; one chromosome becomes 2 sister chromatids.
    S phase
  8. In __, the cell prepares for mitosis. There are now __ chromosomes and __ sister chromatids.
    G2; 46; 92
  9. different DNA sequences that code for the same protein
    homologous pairs
  10. Mitosis and cytokinesis occur during this phase
    M phase
  11. Some cells no longer divide, or divide infrequently and need signals called __ - external chemical signals that stimulate these cells to divide. An example would be __
    growth factors; erythropoietin

    (Erythropoietin is produced in the kidneys & stimulates division of bone marrow cells and production of red blood cells)
  12. The DNA molecule is complexed with proteins to form dense __. __ coat DNA - make it compact at the end of G2.
    chromatin; condensins
  13. Packaging of DNA is achieved by __ - proteins with __ charges that attract __ phosphate groups of DNA. Interactions result in the formation of beadlike units, or __
    histones; positive; negative; nucleosomes

    (page 16 on slide)
  14. The __ determines the plane of cell division. It __ during __ and will determine spindle orientation.
    centrosome; doubles; S phase
  15. Each __ can consist of __ - hollow tubes formed by microtubules at right angles
    centrosome; 2 centrioles

    (page 19 and 25 on slide)
  16. The __ move to opposite ends of the nuclear envelope during G2 to M transition.

    (page 25 on slide)
  17. The sister chromatids are held together by __, which is removed during __ except at the __.
    cohesin; prophase; centromere

    (page 30 on slide)
  18. During prophase __, for movement, develop in the __ regions. __ serve as mitotic centers or poles.
    kinetochores; centromere; Centrosomes

    (page 25 on slide)
  19. During prophase, microtubules form between the poles to make the spindle. The spindle has 2 types of microtubules:
    • polar microtubules: form spindle, overlap in center
    • kinetochore microtubules: attach to kinetochores on the chromatids. Sister chromatids attach to opposite halves of the spindle

    (page 25 on slide)
  20. During __, the nuclear envelope breaks down.

    (page 27 on slide)
  21. During __, chromosomes line up at the midline of the cell.

    46 chromosomes line up one on top of each other.

    (page 28 on slide)
  22. During __, the sister chromatids separate because __ is removed from the centromere. After separation they move to opposite ends of the spindle and are referred to as __
    anaphase; cohesin; daughter chromosomes (92)

    (page 29 and 30 on slide)
  23. __ occurs after chromosomes have separated. Spindle breaks down, chromosomes uncoil, nuclear envelope & nucleoli appear. 2 daughter nuclei are formed with identical genetic information.

    92 daughter chromosomes are splitting into 2 cells each with 46 chromosomes.

    (page 32 on slide)
  24. __ occurs when the plasma membrane pinches between the nuclei because of a contractile ring of microfilaments.
Card Set:
Cell Cycle & Cell Division part 1
2016-11-20 19:34:25

Week 8
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